Multi-layer pipe assemblies are commonly utilized to convey oil, gas, and/or other suitable fluids. In particular, such pipe assemblies are employed in the oil and gas industry, such as in subsea applications as well as in oil and gas production fields. In on-shore or subsea applications, for, example, multi-layer pipes may be utilized in risers, transfer lines, umbilicals and/or other suitable pipe assemblies. In production field applications, multi-layer pipes may be utilized in risers, infield flow lines, export pipelines and/or other suitable pipe assemblies.
Multi-layer pipe assemblies, and the pipe sections thereof, typically include at least two layers; a hollow body or inner layer, and a barrier layer or outer layer generally surrounding the hollow body. Other layers may further be included generally surrounding the barrier layer. Various materials have been utilized to form each of these layers in an effort to improve various performance characteristics of the resulting pipe sections. Additionally, these layers have been bonded together or left unbonded, depending on the application and the desired performance of the pipe section. For example, U.S. Pat. No. 5,876,648 discloses a pipe section having a metal inner layer and an outer layer formed by particular shrinkable polymers. U.S. Pat. No. 6,039,083 discloses a pipe section having a metal inner layer and an outer layer formed by particular polymers. U.S. Pat. No. 8,210,212 discloses a pipe section having a metal inner layer and a polymer outer layer. U.S. Pat. No. 8,163,364 discloses a pipe section having a polymer layer and a film layer. U.S. Patent Application No. 2009/0301594 discloses a pipe section having a metal inner layer and an outer layer formed from a polyphenylene sulfide (PPS). U.S. Patent Application No. 2010/0326558 discloses a pipe section having an inner layer and a polymer outer layer. U.S. Patent Application No. 2011/0041947 discloses a pipe section having a thermoplastic inner layer and a tape outer layer bonded to the inner layer. Japanese Patent No. 3021435 discloses a pipe section having a thermoplastic inner layer and a tape outer layer.
The materials utilized in such known pipe assemblies do not provide the characteristics required for many applications. For example, in many cases, pipe assemblies are undesirably heavy. Lightweight pipe assemblies formed using polymer materials such as those described above, however, may not exhibit both the flexibility and high strength and resistance properties required by, for example, oil and gas applications.
Polymer blends that exhibit flexibility in addition to high strength and resistance properties are of significant commercial interest. Such blends have been formed in the past by uniformly mixing an elastic component with a thermoplastic polyolefin such that the elastomer is intimately and uniformly dispersed as a discrete or co-continuous phase within a continuous phase of the polyolefin. Vulcanization of the composite crosslinks the components and provides improved temperature and chemical resistance to the composition. When vulcanization is carried out during combination of the various polymeric components it is termed dynamic vulcanization.
Polyarylene sulfides are high-performance polymers that may withstand high thermal, chemical, and mechanical stresses and are beneficially utilized in a wide variety of applications. Polyarylene sulfides have often been blended with other polymers to improve characteristics of the product composition. For example, elastomeric impact modifiers have been found beneficial for improvement of the physical properties of a polyarylene sulfide composition. Compositions including blends of polyarylene sulfides with impact modifying polymers have been considered for high performance, high temperature applications.
Unfortunately, elastomeric polymers generally considered useful for impact modification are not compatible with polyarylene sulfides and phase separation has been a problem in forming compositions of the two. Attempts have been made to improve the composition formation, for instance through the utilization of compatibilizers. However, even upon such modifications, compositions including polyarylene sulfides in combination with impact modifying polymers still fail to provide product performance as desired, particularly in applications that require both high heat and/or chemical resistance and high impact resistance.
Accordingly, improved pipe sections and assemblies formed from such pipe sections are desired in the art. In particular, pipe sections that utilize polyarylene sulfide compositions that exhibit high strength characteristics and flexibility as well as resistance to degradation, even in extreme temperature environments, while maintaining desirable processing characteristics, would be advantageous.